But, arsenal aside, law enforcement interest in Gentile appears to lie elsewhere: The FBI suspects the old-school Hartford hustler could have inside information about the world's biggest, most baffling art mystery — the theft on March 18, 1990, of 13 masterworks from Boston's Isabella Stewart Gardner Museum.

Three Rembrandts, a Vermeer, a Manet and five drawings by Degas vanished. Two of the paintings — "Storm on the Sea of Galilee," Rembrandt's only known seascape, and Vermeer's "The Concert," each could be worth than $50 million in an open market. All the stolen pieces might be worth $300 million or more.

The circumstances of the arrest have started speculation that the drug case is an effort to leverage Gentile to talk about the Gardner job, if he has anything to talk about.

"I can't say that's what the criminal case is about," Richard S. Cramer, Gentile's court-appointed lawyer, said last week. "But I think its going to be a factor in the mind of the government."

It is not likely that the paintings will have any firm value placed on them any time soon. Pressure by police agencies around the world to resolve the world's highest profile art case makes a public sale an impossibility. That has created one of the big mysteries associated with the Gardner theft: What happened to the art?

At least two thieves were involved in the theft. They dressed as police officers and used the uniforms to trick one of two museum guards into opening a door at about 1:30 a.m., the end of St. Patrick's Day, when celebrations around Boston were winding down.

The Gardner, a century-old, Italianate mansion, was protected by an outdated security system. The thieves bound the guards with duct tape and, fewer than 90 minutes later, drove away into the night in a red car. There has been one lead with any promise over 22 years, according to the museum. It went nowhere.

Police investigators say Gentile has been a player for decades in Hartford-area organized crime, a fraternity thinned to near oblivion over the past 20 years by the FBI, competition from legal gambling casinos, shifting demographics and old age.

Gentile, however, survived. A federal prosecutor described him in court last week as a sworn member of a Philadelphia-based organized crime group. Another source said Gentile was "made" by the Gambino crime family organization in Philadelphia in the late 1990s, through contacts Gentile made in Boston. It was in Boston that Gentile came to the attention of the Gardner investigators.

Gentile claims to have worked for years, with little success, in the used car business. But an investigator said that, whatever Gentile does, it pays enough to keep his family in a comfortable house in a comfortable suburb. He has largely avoided publicity, with a few exceptions. There was one incident, in 1994, when he was charged with larceny and accused of cheating his siblings out of their father's estate.

His latest arrest began as a minor matter. He and a partner, Andrew Parente, are accused of selling fraudulently obtained prescription pain pills. During the search of Gentile's home, the FBI found only about 80 pills.

It was the other stuff the FBI found — the guns, bullets, explosives, a bullet-proof vest, a sap, $20,000 stuffed in a grandfather clock with a set of brass knuckles — that raised the profile of the case and Gentile's criminal liability. It is a crime for a convicted felon, as Gentile is, to own many of the items found in his home. In some cases, convictions can carry a mandatory prison sentence.

Gentile's friends suggest that the FBI is using a "nickel and dime" drug case as leverage to make an overweight senior citizen with a bad heart and bad back give up, once and for all, whatever he might know about the Gardner job. And the claims he has nothing to give.

"They're putting the squeeze on him so he'll open up on other things," said Parente, arrested with Gentile recently. "They mentioned it, about the pictures, when they picked me up and took me down to the federal joint. I don't know nothing about no pictures."

Parente was released on bond after his arrest, unlike Gentile, who was held in jail when a judge said the search of his house revealed a "propensity toward violence."

Parente said that FBI agents have been trying to question Gentile about the Gardner for years and that Gentile has been denying knowledge of the theft for just as long. There is a $5 million reward and a promise of no prosecution for anyone who helps recover the paintings.

"He told me they offered him $5 million," Parente said. "I don't know if that's true. But that would be a hard thing to turn down, wouldn't it?"

"He don't know where they are," Parente said of the stolen artworks. "Bobby lives a quiet life. He doesn't drive a brand new car. He's got a home that's been paid for for years, that he built. They are really, really exaggerating this. And this bust is more exaggeration than anything. I'm 75 years old and I took a pinch because of it. It's ridiculous."

An FBI spokesman said the bureau "does not comment on pending investigative matters."

But retired investigators said last week that organized crime informants in Hartford were talking about the Gardner job soon after it took place and, on at least one occasion, they dropped Gentile's name. An informant reported in 1990 that someone from Hartford was connected to the art theft. By 1993, another informant had mentioned Gentile specifically.

In 2010, the FBI tried to question Gentile after learning he had become friendly, years earlier, with a Boston-area man named Robert Guarente. Guarente was associated with a crew of gangsters who met at an auto repair shop in Dorchester owned by Carmello Merlino. Merlino, who was seen frequently with a capo in the Patriarca crime family, is a suspect in the Gardner theft.

According to two sources, Gardner investigators became interested in events that occurred before Guarente's death in 2004, including that Guarente moved to Maine. The FBI got a tip that one or more of the paintings may have been hidden in Maine, perhaps by Guarente. Gentile visited Guarente in Maine. When the investigators later looked for paintings in Maine, they found none.

Gentile has admitted knowing Guarente, the two sources said. But they said he insists that, whatever he knows about stolen paintings, he learned from the newspaper.

"He's been going back and forth to a grand jury and stuff like that," Parente said. "But he doesn't know nothing about no paintings."

Cramer, Gentile's lawyer, said the "government is wasting its time going after a sick, debilitated old man on the mistaken belief that he has millions of dollars in paintings."

"They offered him $5 million" Cramer said. "He would love $5 million. He doesn't know. Can't help. But they are not going to give up."